Modern shells are powerful enough to help you remember, if you learn to configure them appropriately. My histories are always saved because each shell instance gets its own HISTFILE, like so:

  export HISTFILE=$HOME/.history/${TTY##\*/}.$SHLVL

As I use different terminal windows for different tasks, this keeps history files rather concise thematically.

And I let the shell add timestamps too, so I can grep for entries produced during a certain time span:

zsh:

  setopt EXTENDEDHISTORY # add timestamps

bash:

  HISTTIMEFORMAT="%F %T "

I write perl or shell script files, of course, if it's more than some a handful of lines.

I do something similar, I gave up on trying to get the bash history to work properly and so just have this:

    echo "$HOSTNAME $$ $(date "+%Y-%m-%dT%H:%M:%S%z") $*" >> ~/.fullhistory

It's attached to the preexec hook of https://github.com/rcaloras/bash-preexec, so is run before every command. This means that everything goes into one easily-greppable file, but is still separable by PID/host machine - since my work has me walking around a large facility, often I'll remember where I was when I did something but not exactly when, so can narrow down by machine.